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15494 Views 11 Replies Latest reply: Feb 17, 2009 7:21 AM by Scott Morris - CCDE/4xCCIE/2xJNCIE RSS

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Dual Internet Load Balancing WITHOUT BGP???

Dec 4, 2008 10:18 PM

Mark DeLong 15 posts since
Oct 11, 2008

 

Hello,

 

 

I just passed a Cisco SMB Field Engineer cert for my company and one of the persistent ideas is redundancy through dual internet connections on one or more routers. In the SMB, I figure that the chances are that this is going to probably be on one single router to keep the price point low in many deployments.

 

 

While going through the CCNP the only way I learned how to do load balancing over multiple Internet connections was by using BGP. I understand that you can still have redudancy with two or more internet connections (not using BGP) on a router using something as simple as a floating static route but I figure there has to be a way to also "load balance" the connections without using BGP. Who wants to configure BGP in an SMB after all?? I'm talking a small biz with a cable modem and a dsl link or maybe a TLS and a DSL backup or something of the sorts. Probably on something like a 2811 router? Is there a really simple way to load balance internet connections on a Cisco router? Or maybe the BGP way isn't really a big deal and I'm just making too big a deal out of it as the truth is I've never had to configure it since I got my CCNP.

 

 

I have seen a few examples that look like they might do this using NAT, Route Maps, and SLA on Cisco.com and other places. To tell truth though I'm still not sure if I'm reading the right thing as the explanations are either non-existant or low on content.

 

 

So does anyone know an easy way for a SMB to load balance over two Internet Links on a single cisco router like a 2811? I would appreciate an answer because I just can't believe that BGP is the only answer. If it is than so be it but there has to be another (read easier) way!

 

 

 

 

 

Thanks for Your Help!!!

 

 

  • Conwyn 7,914 posts since
    Sep 10, 2008
    Currently Being Moderated
    1. Dec 4, 2008 10:47 PM (in response to Mark DeLong)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    Hi Mark

     

     

    Optimised Edge Routing (OER) measures response times and then will determine the fastest response and choose the best ISP to use for each individual IP address. See www.cisco.com for details.

     

     

    Regards Conwyn

     

     

  • Matt Kerry 283 posts since
    Jun 26, 2008
    Currently Being Moderated
    3. Dec 4, 2008 10:57 PM (in response to Mark DeLong)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    I've never tried this with a Cisco router but the easiest way I have deployed ISP redundancy (not load balancing) is with a PIX/ASA firewall. Config example can be found here:

     

     

    http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a00806e880b.shtml

     

     

    thanks ,

     

     

    matt

     

     

     

     

     

  • Conwyn 7,914 posts since
    Sep 10, 2008
    Currently Being Moderated
    7. Dec 5, 2008 12:27 AM (in response to Mark DeLong)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    Hi Mark

     

    OER is more clever than their example. See the manual below *

    Cisco IOS Optimized Edge Routing Configuration Guide

     

     

    http://www.cisco.com/en/US/docs/ios/oer/configuration/guide/12_4/oer_12_4_book.html

     

    Regards Conwyn

     

    *

     

     

     

     

     

     

     

  • Scott Morris - CCDE/4xCCIE/2xJNCIE 8,395 posts since
    Oct 7, 2008
    Currently Being Moderated
    8. Dec 5, 2008 4:35 AM (in response to Conwyn)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    OER can be quite festive in its configuration, however, it's designed as a "more than one router" solution.

     

     

    Definitely in the "S" part of "SMB" it'll be hard to manage with that. As stated in the original message, chances are that there will be a single router. If you have more than one router, just advertise multiple 0/0 routes inside your network with equal cost and other routers will load balance.

     

     

    If you have one router, you're going to be relegated to nat with route-maps (unless you have your own static/public addresses that work over both circuits).

     

     

    HTH,

     

     

    Scott

     

     

     

     

     

  • Ronald Angello 281 posts since
    Jun 2, 2008
    Currently Being Moderated
    9. Feb 16, 2009 8:41 PM (in response to Mark DeLong)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    You can load share with static routes. Both customer edge routers would have a static default route, and you can redistribute them into your IGP. To optimize return traffic, each provider edge router advertises only a part of the customer's address space into the provider backbone, but also advertises the whole customer address space for backup purposes.

     

     

  • Conwyn 7,914 posts since
    Sep 10, 2008
    Currently Being Moderated
    10. Feb 16, 2009 11:01 PM (in response to Ronald Angello)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    Hi Ronald

     

     

    I am happy with having multiple static routes with the same metric with in the IGP but can you explain a little more how you can have different default routes with the same metric to achieve load balancing within the IGP. That sounds very interesting.

     

     

    Regards Conwyn

     

     

  • Scott Morris - CCDE/4xCCIE/2xJNCIE 8,395 posts since
    Oct 7, 2008
    Currently Being Moderated
    11. Feb 17, 2009 7:21 AM (in response to Conwyn)
    Re: Dual Internet Load Balancing WITHOUT BGP???

     

    Your load balancing is done (presumably) on the single router with multiple paths out to the Internet.

     

     

    All other routers internally don't need to care about dual paths. They need to get to that exit/gateway router only. So your IGP configuration is actually quite simple, just a default information command and away you go!

     

     

    Very often we try to make things far more difficult than they really are! Analyze your connection layout and see who needs to know about the multiple choices for exiting the network and who doesn't care!

     

     

    HTH,

     

     

    Scott

     

     

     

     

     

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